Results 1 to 3 of 3
Like Tree1Thanks
  • 1 Post By Gusbob

Math Help - Cardinality- Set theory

  1. #1
    Newbie
    Joined
    Apr 2013
    From
    Saudi Arabia
    Posts
    2

    Question Cardinality- Set theory

    Hello,

    I have been reading this book to brush up on what I have learned, but I the following is a bit confusing, please see if I got it correctly..

    any set say
    X = {dog, {} } |X| = 2
    Y = {dog} |Y| = 2 ?

    I figured since {} is a subset of any set, then it will be by default a part of all sets..

    another one is
    Z= {1,2,3,4,5} |Z| = 6 ... same reason as above ,,,


    Thank you.

    Best regards,
    Amait
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Jan 2008
    Posts
    588
    Thanks
    87

    Re: Cardinality- Set theory

    Quote Originally Posted by Amait View Post
    X = {dog, {} } |X| = 2
    Y = {dog} |Y| = 2 ?

    I figured since {} is a subset of any set, then it will be by default a part of all sets..
    The difference between the X and Y is that \{\} is an element of the set X vs \{\} is a subset of the set Y. The cardinality of X and Y only counts the number of elements, NOT the number of subsets. So |X|=2,|Y|=1. Similarly, |Z|=5
    Thanks from Amait
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Apr 2013
    From
    Saudi Arabia
    Posts
    2

    Re: Cardinality- Set theory

    Thanks that is very much clear !
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Cardinality
    Posted in the Number Theory Forum
    Replies: 5
    Last Post: September 13th 2012, 09:15 AM
  2. Cardinality
    Posted in the Discrete Math Forum
    Replies: 5
    Last Post: May 11th 2010, 08:08 AM
  3. Cardinality of a set
    Posted in the Discrete Math Forum
    Replies: 3
    Last Post: April 29th 2010, 05:03 PM
  4. Cardinality
    Posted in the Discrete Math Forum
    Replies: 2
    Last Post: October 7th 2009, 01:34 PM
  5. Cardinality of a Set
    Posted in the Discrete Math Forum
    Replies: 3
    Last Post: January 27th 2009, 04:33 PM

Search Tags


/mathhelpforum @mathhelpforum